Wim Hof breathing and breathwork · what the trials measured
Plate 46
Breath record
What a study breathed
16
Sources on the page
5
Goals in people
On this page. Counts, not a grade and not a ranking.
No goal on this page meets the rule for a stronger record. The rule is printed above the goals, and the count it read is printed under each one.
Read this first
Educational use only. This page is not medical advice. Breathing patterns and session lengths are what a study ran, not a practice for you. Hyperventilation followed by breath holding can cause fainting without warning, and in or near water it can kill. Epilepsy, heart disease and pregnancy are questions for your own clinician. Aaron Cuha is a coach, not a doctor.
Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use.
The Wim Hof Method combines three parts: a breathing pattern of rounds of fast, deep breaths followed by a breath hold after exhaling, cold exposure, and a meditation or commitment element. Its breathing part alone is sometimes studied as Wim Hof breathing; in the research it is called cyclic hyperventilation with breath retention.
Breathwork is the wider family: slow breathing, box breathing, cyclic sighing with long exhales, and fast high-ventilation practices like Wim Hof's. They do different things to blood chemistry, and the evidence for one does not transfer to another. This page keeps them apart.
The fast breathing blows off carbon dioxide, which makes the blood more alkaline, and the breath hold that follows lets oxygen fall. In one study, finger oxygen saturation reached 60 percent at the end of the holds. Those swings are the proposed mechanism, and the source of the main risk.
The proposed story is that the breathing deliberately triggers a surge of adrenaline, which damps the immune system's inflammatory response. That part was measured in a laboratory, in healthy men given a bacterial toxin. Whether it matters outside that laboratory is the open question.
Adrenaline damps inflammation
In healthy men, 12 of them given 10 days of training in breathing, cold and meditation raised adrenaline during practice; after a bacterial toxin, the trained men had higher anti-inflammatory IL-10, lower inflammatory cytokines and fewer flu-like symptoms than untrained men.
The breathing is the active part
In 48 men given the same toxin, cold training alone did not change the inflammatory response; the breathing exercise did, and adding cold enhanced it. The adrenaline rise held whether the method's creator or an independent trainer taught it.
Fast breathing changes brain and body chemistry
A review of high-ventilation breathwork describes marked changes in experience and in the central and autonomic nervous systems, and says the proposed therapeutic uses still need rigorous testing.
Where the mechanism story is weak
In 42 people randomised to 15 days of daily Wim Hof practice or control, heart rate, heart rate variability, blood pressure, arterial stiffness, stress, affect and vitality did not change.
In 15 runners, a Wim Hof breathing session before repeated sprints did not change power or fatigue, despite large changes in blood oxygen and carbon dioxide.
The authors of a breathwork meta-analysis that found lower stress also urge caution to avoid a miscalibration between hype and evidence, citing moderate risk of bias in most trials.
Every number here is what a study ran, named beside it. None is a practice for a reader. Fast breathing and slow breathing are different techniques with different evidence, so the technique matters more than the minutes.
Each row is a record from a paper. It is not a practice for you.
| Goal | Who | What the trial ran | Source |
|---|---|---|---|
| Inflammation, laboratory | 12 trained and 12 untrained healthy men | 10 days of training in meditation, cyclic hyperventilation with retention and ice-cold immersion, then a bacterial toxin in a vein. | PMID 24799686 |
| Heart and mood | 42 participants | Daily Wim Hof practice for 15 days, against control. | PMID 37845341 |
| Wellbeing | 404 healthy adults | 29 days of the Wim Hof Method in person or remotely, against mindfulness meditation. | PMID 41388053 |
| Mood | Adults in a remote randomised study | 5 minutes a day for a month of cyclic sighing, box breathing, cyclic hyperventilation with retention, or mindfulness. | PMID 36630953 |
| Sprinting | 15 amateur runners, crossover | One Wim Hof breathing session before repeated sprints, against hyperventilation alone or normal breathing. | PMID 34514386 |
| Inflammatory spine disease | 24 people with axial spondyloarthritis | 8 weeks of breathing, cold and meditation added to usual care, against a waiting control. | PMID 31790484 |
Stronger records first. Nulls and marketing-ahead goals stay on the same page. Every card is people only; animal work is in its own section below. Nothing here is ranked against the others, and no clinic or device is recommended.
How the tier is decided, so you can check it against the counts printed under each one. Stronger: a clinical guideline or a medical society's indication list recommends it in a named setting, or a pooled analysis of randomised trials favours breathwork and the source rated the certainty moderate. Thin: the pooled result was null or went against breathwork for the goal as named, the source rated it very low, or nothing was pooled at all. Mixed: everything else, including a result that moved one measure and not another.
Mixed, local, or early
12 randomised trials pooled, 785 people; certainty not graded by the source; result mixed
Who was studied
A 2023 meta-analysis of 12 randomised trials and 785 adults across many breathwork styles, one of whose authors is a breath teacher. Then Wim Hof trials: 42 people for 15 days, 404 for 29 days, and 6 trained against 7 untrained expedition members. A one-month remote study compared four practices.
Breathwork lowered self-reported stress (g = -0.35), anxiety and depressive symptoms against control. Exhale-focused cyclic sighing improved mood more than mindfulness. For Wim Hof practice, the 404-person study found greater momentary energy and clarity after sessions with minimal lasting change, the expedition group's depressive symptoms fell, and the 42-person randomised trial found no change in stress, affect or vitality.
Setting in the evidence
Daily practice at home, from 5 minutes to about 20 minutes.
What this does not show
That Wim Hof breathing beats other breathwork or meditation for stress. The pooled result is for breathwork broadly, and the slow and exhale-focused styles did at least as well.
Mixed, local, or early
223 studies pooled; certainty not graded by the source; result mixed
Who was studied
A 2022 meta-analysis of 223 studies of slow breathing, and a randomised trial of 42 people doing daily Wim Hof practice for 15 days.
Slow breathing raised heart rate variability during practice, right after a session and after weeks of practice. Daily Wim Hof practice changed none of heart rate, heart rate variability, blood pressure or arterial stiffness against control.
Setting in the evidence
Slow paced breathing in the pooled studies; Wim Hof breathing in the trial.
What this does not show
A heart benefit from Wim Hof breathing. The positive pooled result belongs to a different technique.
Thin, null, or marketing ahead
nothing pooled; certainty not graded by the source; no pooled result
Who was studied
Healthy men given a bacterial toxin in a vein: 12 trained and 12 untrained in 2014, and 48 in 2022, taught in the 2022 study by the method's creator or an independent trainer. Then 24 people with an inflammatory spine disease and 60 with multiple sclerosis, 43 analysed. A 2024 systematic review of eight trials did not pool them.
After the toxin, trained men had higher IL-10, lower TNF-alpha, IL-6 and IL-8, and fewer flu-like symptoms; the breathing drove it, and cold training alone did not. In spine disease, ESR fell from 16 to 9 mm/hr and disease activity from 3.1 to 2.3, but CRP did not change. In multiple sclerosis, the Wim Hof arm lowered IL-17A and IL-18 about as much as an exercise and diet programme.
Setting in the evidence
Supervised training in breathing, cold and meditation, with the toxin given in hospital.
What this does not show
Fewer infections or better health in daily life. The toxin model is a short laboratory challenge, and the disease pilots were small, open-label and partly compared with no treatment.
Thin, null, or marketing ahead
nothing pooled; certainty not graded by the source; no pooled result
Who was studied
15 amateur runners in a crossover before repeated sprints, and 19 adolescent runners randomised to 4 weeks of daily practice or none.
A breathing session before sprints did not change peak power, average power or fatigue. Four weeks of daily practice did not change breathing frequency, depth or ventilation during a graded exercise test. A 2024 systematic review called the exercise results mixed.
Setting in the evidence
Wim Hof breathing before exercise, or daily for 4 weeks.
What this does not show
Any performance gain.
Thin, null, or marketing ahead
nothing pooled; certainty not graded by the source; no pooled result
Who was studied
Nobody, for this goal. The closest is the 2024 systematic review of eight Wim Hof trials.
The review found possible anti-inflammatory effects and mixed exercise results. None of its trials measured ageing.
Setting in the evidence
Not applicable.
What this does not show
Any lifespan or ageing benefit.
No animal study of the Wim Hof Method, or of cyclic hyperventilation with breath holds as a practice, appeared in the search. This section is empty on purpose, so nobody fills the gap with a guess.
The best-known result is a laboratory model. A bacterial toxin in a vein is a controlled short challenge, and the method changed the response to it. That is a real finding about the nervous and immune systems, not evidence of fewer infections or less disease in daily life.
The breathing, not the cold, drove that result in the follow-up. The cold page has its own record.
Breathwork lowers self-reported stress in pooled trials, but those trials mix many styles, and slow or exhale-focused breathing did at least as well as fast breathing. The one randomised trial of daily Wim Hof practice on heart and mood measures was null.
The documented harm is specific: hyperventilating before a breath hold lets oxygen fall fast without the urge to breathe, which can cause fainting without warning, and in water, drowning.
The blocks above are the studies. The block below is a judgment about what to do with them. It has to say where it goes past the measurements.
Aaron Cuha’s position
This is opinion, not a finding. Everything else on this page is the evidence.
Wim Hof breathing reliably raises adrenaline and damped the inflammatory response in a laboratory toxin model. Beyond that, its trials are small and mixed, the one randomised trial of daily practice on heart and mood found nothing, and slower breathing styles have stronger evidence for calm. Breath holding after hyperventilation can cause fainting, and in water it can kill.
The reasoning
Where this goes beyond the evidence
This position goes beyond the evidence in treating the laboratory result as not transferable: it is possible the same adrenaline response lowers inflammation in disease, and the small spine disease and multiple sclerosis pilots point that way. A large randomised trial in an inflammatory disease, against an active control, would settle it. It also generalises from short trials of 15 to 29 days; longer daily practice has not been tested in a randomised trial.
Who this is not for
Anyone practising in or near water, in a bath, or while driving; anyone with epilepsy, a fainting history, heart disease or pregnancy who has not asked their own clinician; and anyone who wants this page to replace one.
Aaron Cuha, who built this archive and reads the studies behind the pages. He is a coach, not a doctor, and no medical credential is claimed for him anywhere on this site. More about who writes this
Anyone in or near water
In 60 Australian snorkelling deaths, 12 followed breath holding after hyperventilation or on ascent, causing unconsciousness and then drowning.
Anyone with a fainting or seizure history
In one study, oxygen saturation fell to 60 percent at the end of the breath holds. A diver who did the same on land, unsupervised, lost consciousness for a prolonged period.
Anyone expecting a heart benefit
Daily practice for 15 days did not change heart rate variability or blood pressure in a randomised trial.
Anyone wanting a personal practice
Breathing patterns and session lengths here are records of what a study ran. They are not instructions for your body.
Hyperventilating before a breath hold lets oxygen fall fast before the urge to breathe arrives. In 15 runners, finger oxygen saturation fell to 60 percent at the end of the holds. A diver practising this on land, alone, lost consciousness and developed fluid on the lungs.
Of 60 snorkelling deaths in Australia from 1987 to 1996, 12 were from hypoxia with breath holding after hyperventilation, or on ascent, causing unconsciousness and then drowning.
In the spine disease trial, adverse events did not differ from control, and in the multiple sclerosis pilot the method was well tolerated. Both were supervised.
This site teaches a blood panel, protein and training before gadgets and practices. Breathwork does not move that order, though unlike the devices it costs nothing.
Disclosed both ways: the owner of this archive lists Wim Hof breathing in his own protocol at /my-protocols. That is a personal choice recorded there, not a finding on this page.
Nothing on this page is for sale. No seller wrote it, and no course, app or instructor is named or ranked.
Four breathing styles that get grouped together. None is ranked.
Fast breathing with breath holds, cold exposure and meditation, together.
Evidence match. The toxin studies, the spine disease and multiple sclerosis pilots, and the 404-person study.
Mismatch. Most results combine all three parts, so the breathing alone cannot always be separated.
Rounds of fast, deep breaths followed by a breath hold after exhaling.
Evidence match. The sprint and adolescent runner studies, and the breathing arm of the 2022 toxin study.
Mismatch. The performance results were null; the risk is the breath hold.
Long exhales, or equal counts of in, hold and out.
Evidence match. The one-month remote study, where cyclic sighing improved mood most.
Mismatch. One study, 5 minutes a day, remote.
Breathing well below the usual resting rate.
Evidence match. The 223-study meta-analysis of heart rate variability.
Mismatch. Not what the Wim Hof Method does, and its result does not transfer to fast breathing.
Floor habits and the neighbouring pages. None of these is a cart.
Neighbour
The other half of the Wim Hof Method, with its own record.
Neighbour
Another stressor practice, held to the same rule.
Oxygen
What extra oxygen does, and does not do.
Floor
A marker, or a panel you still need. Not a diagnosis.
Disclosure
Where Wim Hof breathing appears in a personal plan, labelled as one.
Order
Measure first. Floor habits before gadgets.
Map
Every pillar, this one among them, held to the same rule.
Knowledge stays free. No seller wrote this page. Every source below opens the record that was checked before the sentence was written, with what it found and who funded it.
Healthy men randomised: 12 trained for 10 days in meditation, cyclic hyperventilation with breath retention and ice-cold immersion, 12 untrained. All then received a bacterial toxin in a vein. The trained group had higher adrenaline, a faster and higher anti-inflammatory IL-10, lower TNF-alpha, IL-6 and IL-8, and fewer flu-like symptoms. The authors declare no conflicts.
Two studies in healthy men. In 40, both breathing exercises raised adrenaline whether taught by the method's creator or an independent trainer. In 48 given the toxin, cold training alone did not change the inflammatory response; the breathing exercise did, and cold enhanced it. Internally funded by Radboud university medical center; no conflicts declared.
Narrative review of fast, deep breathing practices. They produce marked changes in experience and in the central and autonomic nervous systems through blood chemistry and body sensing; therapeutic uses remain to be tested rigorously. Declared interest: one author is a trained breath teacher with a breathwork foundation.
42 participants randomised to 15 days of daily Wim Hof practice or control. No effect on heart rate, heart rate variability, blood pressure, arterial stiffness, perceived stress, affect or vitality, at rest or in a cold test. No competing interests declared.
15 amateur runners, randomised crossover: one Wim Hof breathing session, plain hyperventilation or normal breathing before repeated sprints. No effect on peak power, average power or fatigue. Finger oxygen saturation fell to 60 percent at the end of the breath holds. No conflicts declared.
12 randomised trials, 785 adults, breathwork of many kinds. Self-reported stress was lower than control (g = -0.35), as were anxiety (-0.32) and depressive symptoms (-0.40). The authors urge caution to avoid a miscalibration between hype and evidence. Declared interest: one author trained as a breath teacher with a breathwork foundation.
404 healthy adults, 29 days of the Wim Hof Method in person or remotely, or mindfulness meditation, semi-randomised. Wim Hof practice gave greater momentary rises in energy, mental clarity and ability to handle stress after each session; changes in traits over 29 days were minimal. No competing interests declared.
Remote randomised study: 5 minutes a day for a month of cyclic sighing, box breathing, cyclic hyperventilation with retention, or mindfulness. Breathwork, especially exhale-focused cyclic sighing, improved mood and lowered breathing rate more than mindfulness. One author became an advisor to a wearable company, WHOOP, in June 2022. Funded in part by the NIH eye institute.
24 people with active axial spondyloarthritis, an inflammatory spine disease, randomised to 8 weeks of breathing, cold and meditation or a waiting control. Adverse events did not differ. ESR, an inflammation marker, fell from 16 to 9 mm/hr and disease activity from 3.1 to 2.3; CRP did not change. Open-label. No competing interests declared.
60 people with multiple sclerosis allocated to the Wim Hof Method, a lifestyle programme or control for 12 weeks; 43 analysed. Both programmes lowered IL-17A and IL-18; nerve damage markers did not change. The Wim Hof arm did about as well as exercise and diet counselling. No competing interests declared.
Nine papers on eight trials of the Wim Hof Method or its breathing alone. The method may reduce inflammation through raised adrenaline and IL-10; effects on exercise performance and breathing measures were mixed. Narrative synthesis, no pooling. No competing interests declared.
Observational, expedition members: 6 did 8 weeks of Wim Hof training, 7 did not. Depressive symptoms fell in the trained group; cortisol fell non-significantly. Supported by Charles University and the Czech Ministry of Education; no conflicts declared.
223 studies of slow breathing, a different technique from Wim Hof's fast breathing. Heart rate variability linked to the calming branch of the nervous system rose during, right after and after weeks of practice. No funding or conflict statement in the PubMed record.
19 adolescent runners averaging 16.6 years randomised to 4 weeks of daily Wim Hof breathing, about 20 minutes a day, or none. Breathing frequency, depth and ventilation during exercise did not differ between groups. No conflicts declared.
Case report. A diver hyperventilated and held his breath on land, unsupervised, lost consciousness, and suffered prolonged severe hypoxia with fluid on the lungs. The authors note that hyperventilating before a breath hold lets oxygen fall fast without warning. No funding or conflict statement in the PubMed record.
60 snorkelling deaths in Australia from 1987 to 1996. 12 were from hypoxia with breath holding after hyperventilation, or on ascent, causing unconsciousness and then drowning. No funding or conflict statement in the PubMed record.
Educational use only. This page is not medical advice. Breathing patterns and session lengths are what a study ran, not a practice for you. Hyperventilation followed by breath holding can cause fainting without warning, and in or near water it can kill. Epilepsy, heart disease and pregnancy are questions for your own clinician. Aaron Cuha is a coach, not a doctor.
Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use.